Curious about the lowest choice of screen brightness that might ever be chosen by someone working with photos. 80 cd/m^2 is a common recommendation for editing in a dark room, but is there ever a reason to use a darker screen, say 40 or 20 cd/m^2?


1 Answer 1


No. The purpose of a viewing screen is to emulate the human vision system and make it easier for you to discern details. If you're going to go to print then you need a screen that can show you or emulate the approximate details of that print.

I used to work with screens that were calibrated for radiological purposes. Think medical. Their calibrations were around 0.5 cd/m2 on the low end up to 100 cd/m2 on the high end. However they really needed to be calibrated up to about 300cd/m2 to take full advantage of how the eye perceives both color and luminance.

Going outside of the range simply blocks up the highlights and shadows, and puts additional strain on your eye as it adjusts to the large differences.

The rest of the room also has an impact on your ability to adjust and perceive color, so keeping that 'in spec' as well is important. It'll make your editing day easier.

  • \$\begingroup\$ The ISO standard for photo editing with an LCD monitor is 120 cd/m² (maximum brightness with screen displaying "pure white") in an ambient environment of D50 lighting at 55 lux. For CRT monitors it is (was, LOL) 100 cd/m². 300 cd/m² is way too bright unless the viewing environment is VERY bright. \$\endgroup\$
    – Michael C
    Jan 18, 2020 at 5:49
  • \$\begingroup\$ @MichaelC It's my understanding that 160 cd/m^2 white is recommended for soft proofing (ISO 12646) to correspond to a 500 lux illumination of a print. Many people find that much too bright and sometimes use much less. Then there are the critical graphic peeps that use upward of 2000 lux. Takes a really bright monitor to match that. \$\endgroup\$
    – doug
    Jan 20, 2020 at 2:11
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    \$\begingroup\$ Many of these standards come out of the viewing environment of the target. Some are for print, some are for 'online' viewing, some are outdoor environment, and some are for detection. Each environment has it's own adaptive requirements and take into account the human vision system. \$\endgroup\$
    – J.Hirsch
    Jan 20, 2020 at 15:16
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    \$\begingroup\$ @MichaelC See the 4th slide titled "ISO 3664:2009 – VIEWING CONDITIONS " which shows two viewing conditions. P1 (500 lux)and P2 (2000 lux). For a display to match which is needed to match hard and soft proofs the monitor white cd/m^2 would have to be 160 or 640. Few people operate that high and viewing conditions where one isn't trying to match hard/soft proofs side by side are typically much lower. \$\endgroup\$
    – doug
    Jan 21, 2020 at 4:19
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    \$\begingroup\$ @MichaelC I also use lower levels for normal photo work. Typically 100 cd/m^2 but sometimes bump it up to 160 to compare a soft proof against an adjacent hard proof illuminated at 500 lux. Of course ambient lighting is much lower. I run about 30 lux ambient. I use D50 for both print viewing and monitor but many prefer D55 or D65. \$\endgroup\$
    – doug
    Jan 21, 2020 at 5:27

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